Monitoring biofouling communities could reduce impacts to mussel aquaculture by allowing synchronisation of husbandry techniques with peaks in settlement

Abstract

Fouling organisms in bivalve aquaculture cause significant economic losses for the industry. Managing biofouling is typically reactive, and involves time- and labour-intensive removal techniques. Mussel spat settlement and biofouling were documented over 20 months at three mussel farms within Port Phillip Bay (PPB), Australia to determine if knowledge of settlement patterns could assist farmers in avoiding biofouling. Mussel spat settlement was largely confined to a 2-month period at one farm. Of the problematic foulers, Ectopleura crocea settlement varied in space and time at all three farms, whilst Ciona intestinalis and Pomatoceros taeniata were present predominantly at one farm and exhibited more distinct settlement periods. Within PPB, complete avoidance of biofouling is impossible. However, diligent monitoring may help farmers avoid peaks in detrimental biofouling species and allow them to implement removal strategies such as manual cleaning, and postpone grading and re-socking practices, until after these peaks.

Keywords:

• Mytilus galloprovincialis
• temporal variability
• spatial variability
• Ectopleura crocea
• Ciona intestinalis
• Pomatoceros taeniata

Acknowledgements

The authors thank Lance Wiffen and staff at Sea Bounty Mussels Pty Ltd for transport to the mussel farms, and assistance with plate deployment and retrieval. They also thank staff at the Victorian Marine Science Consortium (Queenscliff), and Rebecca Hull for her assistance with plate sampling. This manuscript benefited from comments from three anonymous reviewers.